The proposed project requests funding to evaluate a system for implementation through the family courts of the New Beginnings Program, an efficacious preventive intervention for youth from divorcing families. The NBP is a 10- session, parenting group that has been evaluated in two university-based randomized experimental trials and has demonstrated positive program effects to reduce multiple problem outcomes at six-years: reduced marijuana, drug and alcohol use, 37% reduction in prevalence of diagnosed mental disorder; reduced externalizing problems, and reduced high risk sexual behavior; and improved grade point average and self-esteem (Wolchik et al., 2008). Mediational analyses indicated that most of these effects were accounted for by improvements in parent-child relationship quality, effective discipline or both. For many outcomes, program benefits were strongest for youth who were at highest risk when they entered the program. Over the past three years, the primary investigators have collaborated with personnel from family courts and service marketing researchers to develop and pilot test components of a system for delivering NBP through the family courts. The proposed research tests the effectiveness of the NBP as delivered in five courts in Arizona. There are four specific aims of this application: 1. Examine whether families randomly assigned to the NBP show greater improvement than those assigned to a brief workshop on measures of positive parenting, youth substance use and mental health problems. Assessments will occur at pre-test, post-test and 6-month follow-up; analyses will test whether program effects on youth outcomes at 6-months are mediated by program-induced effects on parenting at post-test. 2. Test whether the effects of the NBP are moderated by level of child risk at program entry, gender of parent, ethnicity of parent (i.e., Mexican American vs. non-Hispanic Caucasians) or age of child. 3. Examine whether variability in implementation accounts for variability in positive parenting and youth outcomes. Analyses will also test whether relations between dimensions of implementation and outcomes differ across gender of parent and ethnicity. 4. Experimentally test whether a brief telephone engagement interview increases initiation (i.e. attendance at least one session) relative to a standard informational contact for parents who enroll in the NBP (i.e. express intent to attend). The effect of the engagement interview will be tested for the overall sample, and separately for fathers and mothers, and Mexican Americans and non-Hispanic Caucasians. This project lays the scientific foundation for later studies that address the dissemination of the NBP in a large number of courts. The proposed research has important public health implications for preventing substance use and mental health problems that have substantial individual and societal costs in the 1.5 million U.S. children whose parents divorce each year.